Light pollution might be making spring start a week early

A new study conducted by researchers in the UK suggests that urban light pollution might be causing trees to produce buds earlier than normal, bringing forth an early spring.

Yup, thanks to the bright lights of our big cities, the trees think spring is arriving ahead of time, and the new study notes a time shift of up to 7.5 days in the best-lit parts of the country – and this early budburst is likely to have a knock-on effect on other animals and plants too.

It’s the first time the effects of light pollution on plants and trees have been studied at a UK-wide scale, reports Anna Menin for The Guardian. In the new study,13 years’ worth of data was examined, with ‘citizen scientists’ playing an important role by volunteering to make records of when they first spotted leaves on sycamore, oak, ash, and beech trees.

The data was supplied by the conservation charity The Woodland Trust as part of its Nature’s Calendar initiative.

“Analysis of Nature’s Calendar data suggests that increased urbanisation is continuing to put pressure on the natural world, in ways that we could not have foreseen,” said The Woodland Trust’s citizen science manager Kate Lewthwaite.

“As the seasons become less and less predictable, our native wildlife may struggle to keep up with fluctuations that affect habitats and food sources,”added Lewthwaite. “Hopefully, this research will lead to new thinking on how to tackle such issues, and will help influence future development decisions.”

The researchers behind the new study give the example of the winter moth as one insect that could see its life cycle disrupted – these moths feed on fresh emerging oak leaves and birds higher up the food chain rely on them for food.

Caterpillars are another type of insect that synchronises its life cycle to the changing of the seasons and could end up hatching at the ‘wrong’ time, after the leaves they rely on for food have already budded.

“This has got to be bad for nature, particularly because of the knock-on effects,”explained one of the leaders of the research team, Richard Ffrench-Constant from the University of Exeter. “A positive from this research is that we found red lighting to be particularly culpable for this effect. We may now have the opportunity to create ‘smart lighting’ that is kinder to nature.”

To be clear, the study only showed a correlation, not a causation link between light pollution and the onset of spring in the UK – the most artificially lit parts of the country were the ones entering spring the earliest, but there are likely to be other factors involved, and the link needs further investigation.

But local councils in the UK have responsibility for when street lighting is turned on and switched off, and the research may lead to new approaches both in terms of these timings and the types of light used.

This isn’t the only way light pollution is messing with our environment, either: it also obscures our view of space.

The scientists behind the new study were also keen to praise the role of citizen scientists in helping to collect ‘meaningful’ data on the changing of the seasons.